Simulation test method for impedance characteristic sensitivity of new energy unit

Abstract

The invention discloses a new energy unit impedance characteristic sensitivity simulation test method, which comprises the steps of setting unit control parameters as operation parameters, and obtaining admittance parameters of a unit under each frequency through a hardware-in-loop test method; alternating current power grid side impedance is calculated, and a grid-connected system total impedance open-loop transfer function is calculated according to the admittance parameters and grid-connected system impedance; and calculating the grid-connected oscillation frequency and the phase margin according to the system total impedance open-loop transfer function, changing unit control parameters, and recalculating the grid-connected oscillation frequency and the phase margin. The method can calculate the impedance characteristic parameter sensitivity without obtaining the structure and parameters of the new energy unit controller, has the advantages of high efficiency, simplicity in implementation and the like, and is particularly suitable for the condition that the structure and parameters of the new energy unit controller are unknown.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy unit testing, and in particular to a new energy unit impedance characteristic sensitivity simulation testing method. Background Art

[0002] The grid-connected new energy uses power electronic equipment to realize electric energy conversion and transmission. The multi-time scale control characteristics of power electronic equipment have a profound impact on the wide-band frequency domain characteristics of the new energy power generation system, resulting in wide-band oscillation phenomenon in wind power, photovoltaic and other new energy grid-connected systems. The nonlinear strong coupling control characteristics of power electronic equipment further make the wide-band oscillation phenomenon have complex oscillation characteristics of oscillation frequency coupling.

[0003] In terms of oscillation mechanism analysis, there are mainly eigenvalue analysis and impedance analysis. The advantage of impedance analysis is that the impedance model of the asynchronous power source can be obtained by measurement, without relying on the internal structure and parameters of the asynchronous power source. Large-scale new energy stations are composed of a large number of new energy units connected by cables or submarine cables. The electrical topology in the new energy station has a great influence on the impedance characteristics of the new energy station. At the same time, the topology in the station may also change with the change of operation mode. In practical applications, it is necessary to consider the actual topology of the new energy station and the impact of its changes.

[0004] The unit impedance model can be obtained through analytical modeling and simulation testing. The analytical modeling method requires the controller structure and control parameters, which are difficult to obtain in actual engineering, bringing great challenges to modeling. Summary of the invention

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, in order to solve the problem that the impedance model cannot be analytically modeled and the traditional impedance characteristic parameters cannot be calculated due to the black box of the new energy unit controller, the present invention proposes a new energy unit grid-connected impedance sensitivity simulation test method, which is used to calculate the parameter sensitivity of the impedance characteristic of the new energy unit. This method can calculate the impedance characteristic parameter sensitivity without obtaining the structure and parameters of the new energy unit controller. It has the advantages of high efficiency and simple implementation, and is particularly suitable for situations where the structure and parameters of the new energy unit controller are unknown.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions, a simulation test method for impedance characteristic sensitivity of a new energy unit, comprising:

[0008] Set the unit control parameters as the operating parameters, and obtain the unit's admittance parameters at each frequency through the hardware-in-the-loop test method;

[0009] Calculate the AC grid side impedance, and calculate the total impedance open-loop transfer function of the grid-connected system based on the admittance parameters and the grid-connected system impedance;

[0010] The grid-connected oscillation frequency and phase margin are calculated according to the open-loop transfer function of the total system impedance, and the control parameters of the unit are changed to recalculate the grid-connected oscillation frequency and phase margin.

[0011] As a preferred solution of the impedance characteristic sensitivity simulation test method of the new energy unit described in the present invention, wherein: the admittance parameters at each frequency include: establishing a hardware-in-the-loop test system for the new energy unit, applying a small harmonic voltage disturbance Vh(fh) at different frequencies, and obtaining the harmonic current response Ih(fh) of the unit, then the admittance at frequency fh is Y F(fh) =Ih(fh) / Vh(fh), where Y F(fh) It is a plural number.

[0012] As a preferred scheme of the simulation test method for the sensitivity of impedance characteristics of new energy units described in the present invention, wherein: the calculation of the impedance on the AC power grid side includes obtaining the impedance characteristics of the system at different frequencies Zs(fh)=R0+j(fh*X0 / f0) according to the grid-connected short-circuit impedance Z0=R0+jX0 of the new energy unit, where f0 is the rated frequency of the system.

[0013] As a preferred solution of the impedance characteristic sensitivity simulation test method of the new energy unit described in the present invention, the specific formula for calculating the total impedance open-loop transfer function of the grid-connected system is: Z(fh)=Zs(fh)*Y F(fh) .

[0014] As a preferred scheme of the simulation test method for the impedance characteristic sensitivity of the new energy unit described in the present invention, wherein: the calculation of the grid-connected oscillation frequency and phase margin includes calculating the grid-connected oscillation frequency fo according to the open-loop transfer function Z(fh) of the total impedance of the grid-connected system, that is, the frequency point satisfying |Z(fo)|=1, the corresponding phase margin is Gmar=180-Ang(Z(fo)), Ang(Z(fo)) is the phase of the transfer function Z(fo) at the frequency fo.

[0015] As a preferred scheme of the simulation test method for impedance characteristic sensitivity of new energy units described in the present invention, the calculation of the grid-connected oscillation frequency and phase margin includes, for the control parameter i, changing it by 5%, adjusting it to the original 95% or 105%, repeating the calculation steps, and obtaining the grid-connected oscillation as fo1, and the phase margin as Gmar1.

[0016] As a preferred scheme of the simulation test method for impedance characteristic sensitivity of new energy units described in the present invention, wherein: the recalculation of grid-connected oscillation frequency and phase margin includes calculating the impedance sensitivity of control parameter i as: oscillation frequency sensitivity Sf=fo1-fo, oscillation damping sensitivity Sph=Gmar1-Gmar.

[0017] As a preferred solution of the simulation test method for impedance characteristic sensitivity of new energy units described in the present invention, wherein: the recalculation of the grid-connected oscillation frequency and phase margin includes: the oscillation frequency sensitivity Sf reflects the influence of the control parameter on the oscillation frequency of the grid-connected system, and the greater the sensitivity, the greater the influence on the frequency;

[0018] The oscillation damping sensitivity is the influence of the Sph reaction control parameter on the oscillation damping of the grid-connected system. The greater the sensitivity, the greater the influence on the oscillation damping.

[0019] A computer device includes a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of a simulation test method for impedance characteristic sensitivity of a new energy unit are implemented.

[0020] A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of a simulation test method for impedance characteristic sensitivity of a new energy unit.

[0021] Beneficial effects of the present invention: The method of the present invention can calculate the sensitivity of impedance characteristic parameters without obtaining the structure and parameters of the new energy unit controller, and has the advantages of high efficiency and simple implementation. It is particularly suitable for situations where the structure and parameters of the new energy unit controller are unknown. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0023] Figure 1 A schematic flow chart of a simulation test method for impedance characteristic sensitivity of a new energy generator set provided in one embodiment of the present invention.

[0024] Figure 2 A circuit diagram of a new energy generator set according to a new energy generator set impedance characteristic sensitivity simulation test method provided by an embodiment of the present invention.

[0025] Figure 3A circuit diagram of a new energy generator set and an AC power grid for a new energy generator set impedance characteristic sensitivity simulation test method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0029] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0030] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Example 1, reference Figure 1-Figure 3 , which is the first embodiment of the present invention, and provides a simulation test method for the sensitivity of impedance characteristics of a new energy unit, comprising:

[0033] S1: Set the unit control parameters as the operating parameters, and obtain the unit's admittance parameters at each frequency through the hardware-in-the-loop test method.

[0034] S2: Calculate the AC grid side impedance, and calculate the total impedance open-loop transfer function of the grid-connected system based on the admittance parameters and the grid-connected system impedance.

[0035] S3: Calculate the grid-connected oscillation frequency and phase margin according to the system total impedance open-loop transfer function, change the unit control parameters, and recalculate the grid-connected oscillation frequency and phase margin.

[0036] (1) Figure 2 , 3 As shown, a hardware-in-the-loop test system is established for the new energy unit, and a small harmonic voltage disturbance Vh(fh) at different frequencies is applied to obtain the harmonic current response Ih(fh) of the unit. The admittance at frequency fh is Y F(fh) =Ih(fh) / Vh(fh), where Y F(fh) is a plural number;

[0037] (2) According to the grid-connected short-circuit impedance Z0=R0+jX0 of the new energy unit, the impedance characteristics of the system at different frequencies are obtained: Zs(fh)=R0+j(fh*X0 / f0), where f0 is the rated frequency of the system.

[0038] (3) Calculate the total impedance open-loop transfer function of the grid-connected system: Z(fh) = Zs(fh)*Y F(fh)

[0039] (4) The grid-connected oscillation frequency fo is calculated based on the open-loop transfer function Z(fh) of the total impedance of the grid-connected system, that is, the frequency point that satisfies |Z(fo)|=1. The corresponding phase margin is Gmar=180-Ang(Z(fo)), where Ang(Z(fo)) is the phase of the transfer function Z(fo) at the frequency fo.

[0040] (5) For the considered control parameter i, change it by 5% and adjust it to 95% or 105% of the original value. Repeat steps (1) and (4) to obtain the grid-connected oscillation fo1 and the phase margin Gmar1.

[0041] (6) Calculate the impedance sensitivity of the control parameter i:

[0042] The oscillation frequency sensitivity is Sf=fo1-fo, and the oscillation damping sensitivity is Sph=Gmar1-Gmar.

[0043] The oscillation frequency sensitivity Sf reflects the influence of the control parameter on the oscillation frequency of the grid-connected system. The greater the sensitivity, the greater the influence on the frequency.

[0044] The oscillation damping sensitivity Sph reflects the influence of the control parameter on the oscillation damping of the grid-connected system. The greater the sensitivity, the greater the influence on the oscillation damping.

[0045] The above sensitivity analysis is of great significance for analyzing the influencing factors of oscillation stability and optimizing control parameters.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0047] Example 2

[0048] The second embodiment of the present invention is different from the previous embodiment in that:

[0049] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0050] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0051] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0052] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0053] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0054] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A simulation test method for the sensitivity of impedance characteristics of a new energy unit, characterized by: include, Set the unit control parameters as the operating parameters, and obtain the unit's admittance parameters at each frequency through the hardware-in-the-loop test method; Calculate the AC grid side impedance, and calculate the total impedance open-loop transfer function of the grid-connected system based on the admittance parameters and the grid-connected system impedance; The grid-connected oscillation frequency and phase margin are calculated according to the open-loop transfer function of the total system impedance, and the control parameters of the unit are changed to recalculate the grid-connected oscillation frequency and phase margin.

2. A simulation test method for impedance characteristic sensitivity of a new energy unit according to claim 1, characterized in that: The admittance parameters at each frequency include: establishing a hardware-in-the-loop test system for the new energy unit, applying a small harmonic voltage disturbance Vh(fh) at different frequencies, and obtaining the harmonic current response Ih(fh) of the unit, then the admittance at frequency fh is Y F(fh) =Ih(fh) / Vh(fh), where Y F(fh) It is a plural number.

3. A simulation test method for impedance characteristic sensitivity of a new energy unit as claimed in claim 2, characterized in that: The calculation of the AC grid side impedance includes obtaining the impedance characteristics of the system at different frequencies Zs(fh)=R0+j(fh*X0 / f0) according to the grid-connected short-circuit impedance Z0=R0+jX0 of the new energy unit, where f0 is the rated frequency of the system.

4. A simulation test method for impedance characteristic sensitivity of a new energy unit as claimed in claim 3, characterized in that: The specific formula for calculating the total impedance open-loop transfer function of the grid-connected system is: Z(fh)=Zs(fh)*Y F(fh) .

5. A simulation test method for impedance characteristic sensitivity of a new energy unit as claimed in claim 4, characterized in that: The calculation of the grid-connected oscillation frequency and phase margin includes calculating the grid-connected oscillation frequency fo according to the open-loop transfer function Z(fh) of the total impedance of the grid-connected system, that is, the frequency point satisfying |Z(fo)|=1, and the corresponding phase margin is Gmar=180-Ang(Z(fo)), Ang(Z(fo)) is the phase of the transfer function Z(fo) at the frequency fo.

6. A simulation test method for impedance characteristic sensitivity of a new energy unit as claimed in claim 5, characterized in that: The calculation of the grid-connected oscillation frequency and phase margin includes, for a control parameter i, changing it by 5%, adjusting it to 95% or 105% of the original value, repeating the calculation steps, and obtaining a grid-connected oscillation of fo1 and a phase margin of Gmar1.

7. A simulation test method for impedance characteristic sensitivity of a new energy unit according to claim 6, characterized in that: The recalculation of the grid-connected oscillation frequency and phase margin includes calculating the impedance sensitivity of the control parameter i as follows: the oscillation frequency sensitivity Sf=fo1-fo, and the oscillation damping sensitivity Sph=Gmar1-Gmar.

8. A simulation test method for impedance characteristic sensitivity of a new energy generator set as claimed in claim 7, characterized in that: The recalculation of the grid-connected oscillation frequency and phase margin includes: the oscillation frequency sensitivity Sf reflects the influence of the control parameter on the oscillation frequency of the grid-connected system; the greater the sensitivity, the greater the influence on the frequency; The oscillation damping sensitivity is the influence of the Sph reaction control parameter on the oscillation damping of the grid-connected system. The greater the sensitivity, the greater the influence on the oscillation damping.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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